Mounting of tungsten-halogen lamps



1967 J. w. STRANGE ETAL 3,360,765

MOUNTING OF TUNGSTEN-HALOGEN LAMPS Filed May 27, 1966 United StatesPatent Filed May 27, 1966, Ser. No. 553,426 4 Claims. (Cl. 339-50) Thepresent invention relates to the mounting of tungsten-halogen lamps.These lamps have a tungsten filament enclosed in a quartz or hard glassenvelope with a filling including a halogen such as iodine, and arefinding widespread use as compact light sources.

Because of the small size of the filament its positioning in relation tothe optical system with which the lamp is used is of crucial importance.For example, in one application movement of the filament by .04 inch wasfound to alter the peak intensity of the light beam obtained by 15 to30%. Maintenance of this degree of accuracy in the manufacture of thelamps would be extremely dilficult. The quartz envelope is heated up toa plastic condition and pinched on to each of the leads carrying thefilament. While little movement takes place in the direction of thepinch it is difficult to prevent any movement in a direction at rightangles.

In accordance with the present invention there is provided a mountingassembly for a tungsten-halogen lamp, having at each end of the lamp aU-shaped strap embracing the press of the lamp, the filament lead beingelectrically connected to the strap, a blade-like contact having aforked end whose two arms are secured to the outer faces of the strap,the contact extending from the lamp in the plane of the press in adirection at right angles to that of the filament, and a socketremovably receiving the contact.

With this assembly the filament can be positioned relative to the fixedsockets in a variety of ways in order to achieve exact location of thefilament with respect to a reflector or other optical system. Forexample, the position of the blades relative to the straps may beadjusted before they are secured together by soldering or otherconventional means. Alternatively, the position of each blade in itssocket can be varied by changing the length of the blade or bypositioning of a notch or aperture in the blade which is engaged by adetent or protuberance in the socket.

The accompanying drawing shows one example of a mounting in accordancewith the invention.

The lamp is of conventional form and has a filament in a quartz envelope11 which has presses or pinches 12 at each end. Around each press 12 isa U-shaped strap 13 which is connected at 13a to the lead extendingthrough the press. As is conventional this lead includes a strip ofmolybdenum foil to form a secure seal with the quartz.

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Each of the straps 13 is embraced by a fork, the arms of which are twocopper strips 14 and 15 which extend in the plane of the press 12 and atright angles to the length of the lamp. Each of the strips 14 and 15 isattached at one end to the strap 13 and at the other end to the other ofthe strips to form a blade-like contact for insertion in a socket 165.

The socket 16 is formed by a block 17 of aluminum or brass and a springclip 18 of Inc'onel. The block 17 has a rounded top to guide the contactformed by the strips 14 and 15 to one side of the block. Here it isguided on the other face by inclined prongs 19 projecting from thespring clip 18. It is then gripped between the block 17 and ends 20 'ofthe spring clip 18. The position of the contact is determined by a brassrivet 21 passing through the block 17 and engaging in an aperture 22 inthe contact. The position of this aperture 22 can be altered tocompensate for differences in the position of the filament 10 withrespect to the press 12 in individual lamps. Preferably however theposition of the filament is adjusted by control of the position of thestrips 14 and 15 relative to the straps 13 before they are solderedtogether.

We claim:

1. A lamp mounting assembly comprising a lamp having an envelope, apress at each end of the lamp envelope, a filament enclosed within theenvelope, leads connected to the filament and extending one through eachpress, a separate generally U-shaped strap embracing each press andelectrically connected to one of the leads, each strap having two limbsdisposed on opposite sides of the press, blade-like contacts extendingalong the plane of the presses at right angles to the direction of thelamp filament, each contact having a forked end with two arms which aresecured against the outer faces of the limbs of the corresponding strap,and contact sockets removably receiving the blade-like contacts.

2. A lamp mounting assembly as claimed in claim 1 in which each bladecontact has an aperture and each socket has a detent engageable in theaperture.

3. A lamp mounting assembly as claimed in claim 1 in which each sockethas a rounded block to guide one face of the contact and a spring clipto press against the other face of the contact.

4. A lamp mounting assembly as claimed in claim 1 in which the lamp is atungsten-halogen lamp.

References Cited UNITED STATES PATENTS 2,211,605 8/1940 Moehler 339-52 X2,284,392 5/1942 Heiser 339- 2,705,310 3/1955 Hodge 339-144 2,709,7935/1955 Johansson 339-258 RICHARD E. MOORE, Primary Examiner.

1. A LAMP MOUNTING ASSEMBLY COMPRISING A LAMP HAVING AN ENVELOPE, APRESS AT EACH END OF THE LAMP ENVELOPE, A FILAMENT ENCLOSED WITHIN THEENVELOPE, LEADS CONNECTED TO THE FILAMENT AND EXTENDING ONE THROUGH EACHPRESS, A SEPARATE GENERALLY U-SHAPED STRAP EMBRACING EACH PRESS ANDELECTRICALLY CONNECTED TO ONE OF THE LEADS, EACH STRAP HAVING TWO LIMBSDISPOSED ON OPPOSITE SIDES OF THE PRESS, BLADE-LIKE CONTACTS EXTENDINGALONG THE PLANE OF THE PRESSES AT RIGHT ANGLES TO THE DIRECTION OF THELAMP FILAMENT, EACH CONTACT HAVING A FORKED END WITH TWO ARMS WHICH ARESECURED AGAINST THE OUTER FACES OF THE LIMBS OF THE CORRESPONDING STRAP,AND CONTACT SOCKETS REMOVABLY RECEIVING THE BLADE-LIKE CONTACTS.